From your first picture it seems the unit above yours is not too much higher (unless that's your unit as well). The person on top might not like the sight and noise of your pond as well. You might really want to consider some form of awning or cover up.

Really thanks for all the valuable advises. I have to admit that scenario described by some bros had never come into my mind 😅: dropping fish line from upper unit into my pond to fish; free packet of washing powder, etc. But I know these could really happen if I am unlucky to get just one of this neighbour above me😂

I am currently at the final stage where all my reno and pond are finishing and delivering soon. Thus all I can do is to look into ways to prevent the 'mishap' from happening. Maybe putting some covers over the pond or like what I mentioned earlier, putting a parasol. I believe this is a good learning process for me 😊

Actually I am really touched by my wifey yesterday. I was moody after reading those possible concerns and she came comforting me "Dear, don't worry la, we will have good neighbours above us. Why do you worry so much when you might not even need to. Shouldn't you be happy that your dream is coming true? I thought you always say 船到桥头自然直? Don't worry so much now, we will solve the problems together as they arise along the way. Things will straighten one...."

Suddenly I feel that I am one of the luckiest man in this world, flying to heaven😘
"Maybe we should just keep some simple fish will do..." She added.
Immediately, she sent me back to earth from heaven 😅
Haha... I have a lovely wifey, don't you think so? Love her so much...

Hi TS, I think many bros here has mentioned many points which are valid. Your understanding wife is applauded too but do take note...they are no doubt good neighbours but can u afford to have 1 bad apple?